 /*
  * The contents of this file are subject to the Mozilla Public License
  * Version 1.1 (the "License");  you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  * http//www.mozilla.org/MPL/
  *
  * Software distributed under the License is distributed on an "AS IS" basis,
  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
  * the specific language governing rights and limitations under the License.
  *
  * The Original Code is ART Ontology API.
  *
  * The Initial Developer of the Original Code is University of Roma Tor Vergata.
  * Portions created by University of Roma Tor Vergata are Copyright (C) 2007.
  * All Rights Reserved.
  *
  * ART Ontology API was developed by the Artificial Intelligence Research Group
  * (ai-nlp.info.uniroma2.it) at the University of Roma Tor Vergata
  * Current information about the ART Ontology API can be obtained at 
  * http//ai-nlp.info.uniroma2.it/software/...
  *
  */

  /*
   * Contributor(s): Armando Stellato stellato@info.uniroma2.it
  */
package it.uniroma2.art.owlart.model;


/**
 * the basic RDF element in a RDF graph. Nodes are partitioned by the following three sets:
 * <ul>
 * <li>URIs</li>
 * <li>Blank Nodes</li>
 * <li>Literals</li>
 * </ul>
 * 
 * Moreover, both URI and Literal are considered RDF resources
 * 
 * @author Armando Stellato
 *
 */
public interface ARTNode {

    
	ARTURIResource asURIResource();
	
    ARTResource asResource();
    
    ARTLiteral asLiteral();
    
    /**
     * Answer true iff this STNode is an anonynous resource.
     */
    boolean isBlank();
     
    /**
     * Answer true iff this STNode is a literal resource.
     */
    boolean isLiteral(); 
     
    /**
     * Answer true iff this STNode is a resource
     */
    boolean isResource();
     
    /**
     * Answer true iff this STNode is an named resource.
     */
    boolean isURIResource();
    
    String toString();
    
	public boolean equals(Object o);
	
	public int hashCode();
}
